The ability to genetically modify mice through methods of gene transfer in fertilized mouse embryos (transgenic mice) or gene modification in embryonic stem (ES) cells (gene targeting) has dramatically increased the value and use of mice in biomedical research. . The production of gene-modified mice requires the surgical transfer of embryos into female mice. This surgery requires anesthesia (with potential complications), post-operative care of female mice (which may include the use of analgesics), as well as technical expertise on the part of the person carrying out the surgery, as. At the same time, there is a strong desire in the animal research community to reduce the morbidity, stress and pain of animals used for research purposes. To overcome these problems, we have developed a Non-Surgical Embryo Transfer (NSET) device that can be used for the non-surgical transfer of embryos into female mice. This procedure is rapid (transfer requires about 10 seconds), does not require surgery (including the associated anesthesia and post-operative care), and requires little expertise. Our preliminary data indicate that our NSET device is equally successful as standard surgical embryo transfer in mice in the production of transgenic mice. Preliminary studies were performed with hand-made NSET devices. We have now manufactured a NSET device, enabling us to produce large numbers of NSET devices with a high degree of uniformity. The aims of this proposal are to demonstrate the efficacy of this manufactured NSET device for the non-surgical transfer of embryos that (1) have may be transgenic by DNA microinjection, (2) have been cryopreserved, and (3) were generated by in vitro fertilization of embryos with cryopreserved sperm. Success in these aims will provide the foundation for the commercialization of the NSET device for academic and bio/pharma mouse facilities. PUBLIC HEALTH RELEVANCE: We have developed a device for the non-surgical transfer of embryos into recipient female mice that represents a substantial advance over existing methods of generating gene-modified mice in that it eliminates surgery, including anesthesia and post-operative care. The goal of this proposal is to determine the efficacy of a manufactured non-surgical embryo transfer device for the transfer of embryos that are transgenic, cryopreserved, or generated by in vitro fertilization.